The Vietnam government said on Saturday that the country’s national were among the 39 people who were found dead inside a refrigerated lorry container in the UK’s Essex county last month.

Vietnamese Foreign Minister Pham Binh Minh took to Twitter, saying “There were Vietnamese believed to be among 39 migrants who were found dead in a lorry in Essex”.

“With deepest sorrows, I would like to extend deep sympathy with and sincere condolences to families of the victims,” he wrote.

Earlier, UK police had said that the victims, 31 men and eight women, were Chinese, but a number of Vietnamese families have described how they fear their loved ones are among the dead.

Spokesperson of the Vietnam Foreign Ministry Le Thi Thu Hang said the authorities of the two countries have been closely collaborating to verify the identity of “the victims suspected of being Vietnamese nationals”.

She said they would publish the findings “as soon as possible”.

“Vietnam strongly condemns human trafficking and considers it a serious crime subject to strict penalties. Vietnam calls upon countries in the region and around the world to step up cooperation in combating human trafficking to prevent the recurrence of such (a) tragedy,” she added.

Police believe the container came from Belgium into England, while the truck that transported it is believed to have originated in Northern Ireland.

It is Britain’s largest murder probe in more than a decade.

The deaths echoed the discovery of 58 Chinese immigrants hidden in a Dutch truck in the English port of Dover in 2000. Only two had survived.